Due to a restriction on hardware aspects, such as a lens, an aperture and a sensor, there is a relatively large gap between quality of an image shot by a mobile phone and an image shot by a digital camera, and an image shot by a mobile phone has a relatively low definition. For a cost reason, on a basis that a hardware condition is not improved, image definition can be improved through image sharpening processing.
In the prior art, an image shot is decomposed into a low-frequency base image and a high-frequency detail image using a high-pass filter or a low-pass filter. Because the high-frequency detail image information determines a definition of the image, multiplication is performed on the high-frequency detail image information and a sharpening gain to obtain enhanced detail image information. Then, addition is performed on the base image information and the enhanced detail image information to obtain a sharpened image, thereby improving image definition.
In a process of implementing the present invention, the inventor finds that in the prior art, a phenomenon of overshoot and noise amplification may occur in a sharpened image, thereby causing low image quality.